/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.dx.util;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;

/**
 * File I/O utilities.
 */
public final class FileUtils {

	/**
	 * This class is uninstantiable.
	 */
	private FileUtils() {
		// This space intentionally left blank.
	}

	/**
	 * Reads the named file, translating {@link IOException} to a
	 * {@link RuntimeException} of some sort.
	 * 
	 * @param fileName
	 *            {@code non-null;} name of the file to read
	 * @return {@code non-null;} contents of the file
	 */
	public static byte[] readFile(String fileName) {
		File file = new File(fileName);
		return readFile(file);
	}

	/**
	 * Reads the given file, translating {@link IOException} to a
	 * {@link RuntimeException} of some sort.
	 * 
	 * @param file
	 *            {@code non-null;} the file to read
	 * @return {@code non-null;} contents of the file
	 */
	public static byte[] readFile(File file) {
		if (!file.exists()) {
			throw new RuntimeException(file + ": file not found");
		}

		if (!file.isFile()) {
			throw new RuntimeException(file + ": not a file");
		}

		if (!file.canRead()) {
			throw new RuntimeException(file + ": file not readable");
		}

		long longLength = file.length();
		int length = (int) longLength;
		if (length != longLength) {
			throw new RuntimeException(file + ": file too long");
		}

		byte[] result = new byte[length];

		try {
			FileInputStream in = new FileInputStream(file);
			int at = 0;
			while (length > 0) {
				int amt = in.read(result, at, length);
				if (amt == -1) {
					throw new RuntimeException(file + ": unexpected EOF");
				}
				at += amt;
				length -= amt;
			}
			in.close();
		} catch (IOException ex) {
			throw new RuntimeException(file + ": trouble reading", ex);
		}

		return result;
	}

	/**
	 * Returns true if {@code fileName} names a .zip, .jar, or .apk.
	 */
	public static boolean hasArchiveSuffix(String fileName) {
		return fileName.endsWith(".zip") || fileName.endsWith(".jar")
				|| fileName.endsWith(".apk");
	}
}
